Draft gear



s shets-shee't 1 w. E. GRAY DRAFT GEARv Filed Sept. 2,4 1944 March 18,1947.

March 18, 1947. w." E. GRAY 2,417,410

DRAFT @ma Filed sept. 2, 1944 s Sheets-sheet 2 A IIIIIIIIIIII- March 18,1947. w. E. GRAY DRAFT GEAR Filked sept. 2, 1944 i 15 sheets-smet 3 M QVV KSV/gy? @V K. u

Patented Mar. 18, 1947 DRAFT GEAR William E. Gray, West Lafayette, Ind.,assigner to Peerless Equipment Company, Chicago, Ill., a corporation ofDelaware v Application September 2, 1944, Serial No. 552,511

41ans l This invention relates to draft gears of the type used onrailway cars to frictionally absorb draft and bufiing shocks to whichthe cars are sub-k jected.

More particularly the invention has reference to improvements infriction draft gears, comprising, generally, a housing having frictionsurfaces converging longitudinally thereof, friction shoes forcooperation with said surfaces, a, Wedge for cooperation with said shoesunder draft and bufng loads imposed upon the gear to shift said shoeslongitudinally of the housing in the direction of convergence of saidfriction surfaces and simultaneously to urge said shoes outwardlyagainst said surfaces, and yieldable means tending constantly to shiftsaid shoes longitudinally of the housing in the opposite direction,whereby the gear is caused frictionally to absorb draft and bufiingloads imposed thereon and is released upon release of such loads.

The general objects of the invention are to provide a draft gear of thetype set forth whichis highly efficient in the use of metal and is ofhigh capacity, whereby it may be exceptionally light in weight for anygiven capacity; embodies an exceptionally few number of parts which areof simple design and capablel of being readily and easily produced andassembled, thereby to effect low production cost; is strong, sturdy, andhas large friction areas with provision for overriding of surfaces toprevent shouldering, thusY materially contributing to long life; is oflow mainte nance cost; embodies novel means to insure proper coaction ofits parts; operates with high efiiciency and is constructed topractically and effectively insure its easy release whenever it isrelieved of draft or bufling forces; and is thoroughly reliable inservice.

Another and more specific object of the invention is to provide ahousing with a friction zone of novel shape, including curved andVstraight portions merging into each other in such a manner as toeliminate sharp corners where stresses would otherwise be concentrated,thereby to render the housing well adapted to withstand burstingstresses set up during gear closure. in that connection, it is proposedto provide fric-- tion surfaces and matching shoes having relativelystraight side portions joined by cylindrical portions centered on thelong axis of the entire section, whereby the shoes fit the frictionsurfaces of the housing regardless of their change in position as theyslide in and out of the housing during gear operation. Moreover, thestraight portions and the cylindrical portions permitv of 10 Claims.(o1. 21a-'34) l i attaining the desired pitch for the engaging sur;

Ulu

301equaliaers.will afford a means'of the'wedge ac l Afriction shoest rfaces without resorting to conical surfaces which are not adapted toslide over each .other and do not maintain full contact in allpositions.

A further object is to provide a draft gear having a housing, which whensubjected to stress set up in the direction of the major axis of thefriction zone, due to gear closing, willcause the hous' ing tocontractin the direction of its minor axis, thereby tending to increasethe radial pressure on the straightl portions of the shoes and result inhigher gear capacity. As soon as closing pressure on the gear isremoved, the housing will resume its unstressed state and reduce theradial pressure on the straight portion of the shoes, thereby facili--tating release of the gear.

A still further object of the invention is to or accommodate themselvesto any unavoidable' manufacturing variations in the dimension of parts.These equalizers also have the advantage of maintaining alignmentbetween the wedge and` the front follower in the draft gear pocket andalso enable the friction shoes to line themselves with the frictionsurfaces of the housing. Moreover, should the gears receive angularblow, these commodating itself to the direction of this blowl without'destroying plane Contact between the shoes and the equalizers.

With the foregoing and other objectsl in view,4

which will become more lfully apparent as the nature vof the inventionis better understood, the same consists in the novel features ofconstruction, combination and arrangement of parts hereinafter morefully described, illustrated, and

claimed.

In the accompanying drawings, whereinwlikel characters of referencedenote corresponding parts in the different views:

`Figure 1 is a central, longitudinal section through a draft gearconstructed in accordance with one practical embodiment ofthe'invention.

Figure 2 is a fragmentary central, longitudinal section on the line `2-2of Fig. 1, the wedge being shown inside elevation.

the friction shoes removed therefrom.

Figure 5 is an inner end elevation of one of the;

Figure is across section on the line 3-3 of Figure 6 is an insideelevation of one 0f the friction shoes.

Fig. 7 is a cross section'on the line 'I-l of Fig. 1.

Fig. 8 is an elevation of the wedge looking toward the inner endthereof.

Fig. 9 is a front elevation of one of the disks which are interposedbetween the wedge and the friction shoes.

Fig. 10 is an edge view of the disk shown in` Fig. 9; and A Fig. 11 is aside elevation of the wedge.

Referring to the drawings in detail, I0, IG designate the usual draft orcenter sills of a car underframe structure; II and I2 designate frontand rear stop lugs, respectively, carried by said sills; I3 designates aportion of a draw-bar having operatively associated therewith a yokedesignated as I4, and A designates, generally; the present gear propersupported in its pocket betweenthe sills III, I6 and between the stoplugs II and I2 Vby means of a saddle plate designated as I5, all inaccordance with well known practice.

The gear proper, A, comprises, generally speaking, a housing, designatedas I1; a pair of frictionshoes i8, I8 disposed in the open front endportion I9 of said housing;V one or more helical springs or equivalentyieldable means 2i) in said housing between the closed rear end 2lthereof andthe shoes I8 tending constantly to urge said shoes forwardlyrelative to said housing, and a wedge 22 for urging said shoes outwardlyand rearwardly relative to said housing, all likewise in accordance,generally speaking, with well known practice,

A main front follower 23 is interposed as usual between the wedge 22 andthe front stop lugs I I and in conjunction with said stop lugsconstitutes stop means to limit forward movement of said wedge.Moreover, the draw-bar I3 is operatively associated with said main frontfollower. in accordance with known practice so that bui-ling orrearwardly directed forces imposed upon said draw-bar are transmittedthrough said main front follower'to said wedge 22. On the other hand,there may be a main rear follower similar tothe main front follower 23between the rear of the housing' I'I-and the rear stop lugs I2 and therear of the yoke I 4 in accordance with known practice, orsaid rear stoplugs and the rear of said yoke may cooperate directly with the rear ofsaid housing as shown. In any event, when draft or forwardlyv directedforces are imposed uponpthe yoke HI the housing I 'I isurged forwardlyby said yoke', but since the wedge 22 is held against forward movementby the front stop lugs II and the main front follower 23, the result is1 that said wedge is caused to act to urge the friction shoes i8 .bothoutwardly into tight engagement with. the housing I'I and rearwardlywith respect thereto, whereby the said draft or forwardly directedforces are frictionally absorbed. Conversely, when bufngfor rearwardlydirected forces areimposed upon the draw-bar I3, the main front follower23 and the wedge 22 are urged rearwardlybut since in this case thehousing Il is held against rearward movement by the rear stop lugs I2,the result is,-in effect, the same as results from draft or `forwardlydirected forces being imposed upon the gear; i. e., the wedge 22, is,caused to act to urge the friction shoes I8 both outwardly into tightengagement with the housin g I'1 and rearwardly with respect thereto,whereby the said bufiing or rearwardly directed 4 forces arefrictionally absorbed. Moreover, in each instance the yieldable meansZIJ, which is under compression normally, further is compressed andacts, upon release of the draft or builing force, as the case may betoreturn the friction shoes and the wedge to their normal or forwardmostpositions relative to the housing I'I. All of this, ygenerally speaking,is in accordance with well known practice. j

Y Referring now more ,particularly to the gear proper, A, with which thepresent invention particularly is concerned, it will be observed thatthe open front end portion I9 of the housing I'I is of generally ovalshape in cross section and is regularly rounded at the ends of both itsmajor and its minor axes, as indicated at 24 and 25, respectively. Itwill further be observed that the rounded portions 2d and 25 are joinedby connecting portions 25 which, cross sectionally of the housing Il,are from the rounded portions 2d toward the rounded portions 25 andwhich, in the particular example illustrated in the drawing, arestraight or ilat and are disposed tangentially with respect to saidrounded portions. hereinafter become apparent, however, the connectingportions 26 are not necessarily straight or flat, but may be slightlycurved outwardly if de-` sired. In any event, the rounded portions Mareprovided with internal friction surfacegl of any suitable length whichextend longitudinally of Y the open end portion I9 and preferably are ofcylindrical form and converge inwardly relative to said open endportion. Moreover, the connectingportions 26 are provided withinternalfriction surfaces 28 which may be either flat or curvedoutwardly and which, in any event, con-` stitute smooth continuations ofthe cylindrical surfaces 2'! and cross sectionally of the housing I'Iare flared with respect thereto.

Only two friction shoes i8 are 1 provided and these are ldisposed intheopen end portion I9 at the ends of its major aids, respectively. Theseshoes preferably are sumciently longer than the friction surfaces 21 andV23 to extend Yat all times beyond the ends of said surfaces and therebypreclude the possibility of the wearing of said surfaces in a manner toform shoulders which might interfere with the proper coaction of saidshoes with said surfaces. The shoes I3 may,rhowever, be of the same or.of lesser length than the fric tion surfaces 2l', 28 if desired. In anyevent, each shoe includes an outer, transversely rounded portion 29having an outer preferably cylindrical fric-tion surface 3@ whichcomplements and constantly is engaged with the related frictionv surface21 of the open end por-tion I9 of the'housling Il, and further includesa pair of side or wing portions 3| which extend inwardly from therounded portion 29 and. cross-sectionally of the shoe, are flared withrespect thereto an-d have outer friction surfaces 32 which complementand constantly are engaged with the friction surfaces 28, 28,respectively, the said friction surfaces 32v constituting, of course,smooth, ared continuations of the friction surface t and being eitherflat or curved depending upon whether said friction surfaces 23, 28are-flat or curved.

,Whilethe shoes IB may be of either solid orV hollow form, theypreferably are of light-weight,

Vhollowform and are reinforced rbyfront and rear transverse webs Se andvfLresp'eotively. The rear webs 34, 34 rof the two'shoes have forwardlyand inwardly inclined 'rear faces against which is seated -a disk 35which, in turn, has seated against the rear face thereof the front endof the smaller A As will or inner of two coaxial helical springs 36, 36constituting, in the illustrated embodiment of the invention, theyieldable means 20 for urging said shoes forwardly.. The other or largerof said springs seats at its front end against a ring 3'! which isengaged with the rear ends of the shoes I8, and both springs seat attheir rear ends against the rear end Wall 2l of theA housing il, wherebythey react from said Wall to accomplish their purpose.

The front faces of the front webs 33 are inclined vrearwardly andinwardly and the rear end portion of the wedge 22 is provided withrearwardly and inwardly inclined faces which are opposed to said webfront faces and which they may directly engage if desired. Preferably,however, spherical segments 38 are interposed between the webs 33 andthe related rear faces of the wedge 22, respectively, and areself-ad'usting to Vinsure proper seating cooperation between the frontfaces of said webs and the related rear faces of said wedge at alltimes. To this end, the front faces of the Webs 33 and the rear faces ofthe spherical segments 38 may be flat, while the front faces of saidspherical segments may be of spherical contour and may be seated inrecesses 39 of corresponding spherical contour in the rear of the wedge22 as shown. Alternatively, the rear faces of said spherical segmentsmay-be of spherical contour and may be seated in recesses ofcorresponding spherical contour in the .i fronts of the webs 33 and thefronts of said spherical segments may be flat and may be seated flatlyagainst the rear of the wedge. In either casey the disks 38 obviouslywill accommodate themselves to any misalinement of the wedge and theshoes as well as compensate for any unavoidable manufacturing variationsin dimensions of parts and thus will insure proper seating cooperationbetween said wedge and said shoes at all times, If desired, only asingle spherical segment 38 may be used in lieu of the two sphericalsegments shown. Two spherical segments are preferred, however, asaffording a better balanced structure.

While any suitable means may be provided to maintain the parts of thegear proper, A, assembled as a unit, one practical means for thispurpose may comprise a stop lug or lugs lid projecting inwardly from theopen end portion i9 of the housing i1 at each end of its minor axis andnear the front end thereof, and cooperating lugs d! on ythe wedge 22 atopposite sides thereof.

The free edges of the side or wing portions 3! of the two shoes i8, i3are spaced apart and .between the said free edges of said side or wingportions the open end portion i9 of the housing l'! is devoid of anyobstruction to contraction of the said open end portion of said housingalong its minor axis. In this connection it is apparent that, due to theconnecting portions 25 of the open end portion I9 of the housingr beingflared with respect to the rounded end portions 24 thereof, outwardpressure exerted along the major axis of said open end por-tion I 9 willresult in contraction of said open end portion along its minor axis. Inthis connection, the shoes I8 are, as aforesaid,

disposed at the ends of the major axis of the open end portion I9.Moreover, they are urged outwardly or apart by lthe wedge 22 under draftor leuning forces imposed upon the gear. Accordingly, in response toeither draft or bufng forces imposed upon the gear, the front endportion I9 of the housing l1 is elongated along its major axis and iscontracted along its'minor axis with the result that there is anintensification of pressure and increased friction between thev 1Conversely, when the draft or bufng force is released, expansion orreturn of the front end portion I9 along its minor axis to its normal,unstressed condi-tion results in positive release of the friction shoesi8 for return of the same to their normal forwardmost positions by theyieldable means I8,

summarizing, it is apparent that the present gear proper is ofexceptionally simple construction and is of low production cost due tothe few simple parts of rwhich it is composed; that it is highlyefficient due to the large areas of its friction surfaces, to itsprovision toinsure proper seating of its parts, and to its describedmo-de of operation; that it is well designed to withstand burstingstresses due to the rounding of its open end portion I9 at the ends ofits major and minor axes and the consequent elimination of more or lesssharp corners where stresses might concentrate, and that it is ofstrong, rugged design and therefore will possess long life with littleor no main- -tenance attention. Y

Without further description it is thought that the features andadvantages of the invention will be readily apparent to those skilled inthe art, and it will of course be understood that changesin the form,proportion and minor details of construction may be resorted to,vwithout departing from the spirit of the invention and scope of theappended claims.

I claim:

1. A draft gear comprising a housing having an open'end portion ofgenerally oval form in cross section rounded at the ends of its majorand minor axes and including connecting portions between said roundedportions flared cross sectionally of the housing with respect to therounded portions at the ends of the major axis of said open end portion,the rounded portions at the ends of the major axis of said open endportion having internal friction surfaces of cylindrical form extendinglongitudinally of the housing and converging inwardly relativethereto,said connecting portions having internal friction surfaces constitutingcontinuations of said first mentioned friction surfaces and flared-cross sectionally of the housing with respect thereto, a pair offriction shoes having outer friction surfaces of cylindrical formcomplementing andthe gear to cause said shoes to exert outward pressureupon and to elongate the open end pory tion of said housing along itsmajor axis and to contract the same along its minor axis, thereby tocause said connecting portions to exert inward pressure against the saidside portions of said shoes.

2. A draft gear comprising a housimr having` an open end portion ofgenerally oval form in cross section rounded at the ends of its majorand minor axes and including connecting portions-` between its saidrounded portions flared cross sectionally of the housing with respect tothe rounded portions at the ends of the major yaxis of said open endportion, the rounded portions at the ends of the maior axis of said openend portion having internal friction surfaces of cylindrical formextending longitudinally of said open end portion and converginginwardly relative thereto, said connecting portions having internalfriction' surfaces constituting continuations of saidrst mentionedfriction surfaces and flared cross sectionally of the housing withrespect thereto,'only two friction shoes in said open end portion ofsaid housing disposed at the ends of its major axis, respectively, andhaving outer friction surfaces of cylindrical form complementing andconstantly engaged with said rst men tioned friction surfaces of saidopen end portion, respectively, said shoes further having side portionswith outer fiared friction surfaces compleinenting and engaged' withthel flared inner friction surfaces of said connecting portions, saidshoes being spaced apart and the open end portion of said housingbetween said shoes being devoid 2 of obstruction toY contraction of saidopen end portion along its minor axis, and means operable in response todraft and puffing forces imposed upontl'ie gear to cause said shoes toexert pressure upon and to elongate the open end of said housing alongits major axis and to contract the same along itsminor axis, thereby tocause said connecting portions to exert inward pressure against the saidside portions of saidlshoes.

3. Adraft gear comprising a housing having an open Vend portion of`generally oval form in crosspsection rounded at the ends of its majorand minor axes and including straight lconnecting portions said roundedportions, said straight connecting portions being flared crosssectionally of the housing with respect to the rounded portions at theends of the major axis of said open end portion and aisov being disposedtangentially with respect to said rounded portions, the rounded portionsat the ends of the major axis of said open end portion having internalfriction surfaces of cylindrical form extending longitudinally of saidopen end portion and converging inwardly relativethereto, saidconnecting portions having -flat internal friction surfaces flared crosssectionally of the housing and disposed tangentially with respect tosaid first mentioned friction surfaces and constituting continuations ofthe latter, only two friction shoes in said open end portion of saidhousingidisposed at the ends of its major axis, respectively, and havingouter friction surfaces of cylindrical form complementing and constantlyengaged with the first mentioned friction surfaces of said open endportion, respectively,` said shoes further having side portions with atouter friction surfaces flared and disposed tangentially with respect tothe cylindrical friction surfaces thereof and complementing and engagedwith the nat internal friction surfaces of said connecting portions, andmeans operable in response to draft and bufiing forces imposed upon thegear to cause said shoes to exert outward pressure upon and to elongatethe o-pen end por?v ltion of said housing along its major axis and tocontract the same along its minor axis, thereby to cause said connectingportions to exert inward pressure against the said side portions of saidshoes.

4. A draft gear as set forth in claim 1 in which the open'end portion ofthe housing is of identical reversed contour in ycross section to eitherside of` both its major and its minor axes.' l

` 5. A draft gear as kset forth in claim 3 in which the open end portionof thevho-using is of identical @o ing.

51 wardly converging friction surfaces, frictionshoe's in said open endportion having outer friction surfaces complementing and engaged withthe friction surfaces of said open end portion, respectively, said shoeshaving flat linwardly converging forwardly facing surfaces, a Wedgehaving re-l cesses of spherical contour opposed to said last mentionedsurfaces of said shoes, respectively,

and spherical segments interposed between said wedge and said shoes,respectively, each spherical segment having a dat face engaged with thesaid flat face of the related shoe Aand an opposite face of sphericalcontour complementing and engagedv in the related recess of said Wedge.

7. A draft gear comprising ahousing having O an open end portionprovided withY internal in-*Q wardly converging friction surfaces,friction shoe elements in said open end portion havingouter frictionsurfaces complementing and engaged with the friction surfaces of saidopen end p0rtion, respectively, a wedge element, and spherical segmentsbetween said wedge element andk said f shoe elements, respectively, eachspherical segment having at one'side thereof planar contact with one ofsaid elements and at the opposite side :thereof having spherical contactwith the other ofv said elements.

8.r A draft gear comprising ahousing having an open end portion ofgenerally oval form in cross section rounded at the ends of its majorand minor axes and including connecting portions between said roundedportions flared cross sec' tionally of the housing With respect vto therounded portions at the ends of the major axis of said open end portion,the rounded portions atthe ends of the' major axis of said open endportion having internal transversely rounded friction surfaces whichextend longitudinally of the housing and are uniformly roundedthroughout their lengths, said connecting portions having internalfriction surfaces constituting continuations of said first mentionedfriction surfaces and flared cross sectionally of the housing withrespect thereto, a pair of friction shoes disposed in the open endportion of said housing and having outer rounded frictionv surfacescomplementing and constantly engaged with the rounded internal frictionsurfaces at the ends of the majoraxis of the said open end portion ofsaid housing, respec` v tively, and further having side frictionsurfaces complementing and engaged with the internalr friction surfacesof said connecting portions, and means operable in response to draft andbuiin'g forces imposed upon the gear to urge said shoes apart and intothe open `end portion of said hous- 9. A draft gear comprisinga housinglhaving an open end portion of generally oval form in cross sectionrounded at thev ends ofits major `and ends of the major axis of saidopen end portion having internal transversely rounded frictionsurfaceswhich' extend longitudinally of the housing vin convergingrelationship to each other inwardly with respect to said housing and areuniformlyr rounded throughout their lengths, said connect'- ing portionshaving internal friction surfaces conf stituting continuations of saidfirst-mentioned friction surfaces and flared cross sectionally of thehousing with respect thereto, a pair of friction shoes disposed in theopen end portion of said housing and having outer rounded frictionsurfaces complementing and constantly engaged with the rounded internalfriction surfaces at the ends of the major axis of the said open endportion of said housing, respectively, and further having side frictionsurfaces complementing and engaged with the internal friction surfacesof said connecting portions, and `means operable in response to draftand bufling forces imposed upon the gear to urge said shoes apart andinto the open end portion of said housing.

10. A draft gear comprising a housing having an open end portionprovided with internal friction surfaces converging inwardly relative toeach other longitudinally with respect to said housing, said frictionsurfaces being uniformly rounded transversely throughout their lengths,friction shoes disposed in said front end portion and having externalfriction surfaces conforming to and engaged with said housing frictionsurfaces, and means including a wedge between said friction shoesoperable in response to draft and bufiing forces imposed upon the gearto urge said shoes apartand into the open end portion of said housing.

. WILLIAM E. GRAY.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date 1,200,642 OConnor Oct. 10, 19161,125,109 Johnson Jan. 19, 1915 1,048,729 OConnor Dec. 31, 1912 945,473Nichols Jan. 4, 1910 1,254,857 Sherman Jan. 29, 1918 1,251,930 ShermanJan. 1, 1918 2,222,479 Cottrell Nov. 19, 1940

